1. Technical Field
The disclosed subject matter relates generally to implantable medical devices and more particularly to implantable medical devices that have multiple sequenced therapy protocols.
2. Background Information
Implantable medical devices typically operate according to a desired therapy. A vagus nerve stimulator (VNS), for example, electrically stimulates the patient's vagus nerve in accordance with a therapy that is characterized by such variables as pulse width, pulse amplitude, on time, off time, etc. A physician typically programs settings (pulse width, etc.) in the patient's medical device for a suitable therapy and the settings remain fixed until a physician opts to change the settings.
In at least some situations, however, it is desirable to change the settings. For example, a physician may want to have the patient's brain imaged (e.g., using fMRI or other imaging techniques) while the patient's implanted device is sequenced through multiple sets of settings (i.e., therapies) to determine an optimal therapy. Changing the settings during such imaging unfortunately requires repeated and time-consuming use of specialized programming equipment. By way of a further example, shortly following implantation it may be desired to initialize a setting to a therapeutically relatively low value and change (e.g., increase) that setting until an optimal value is reached for that particular patient. Current magnitude, for example, could be initialized to a relatively low value of current and then ramped up until an optimal patient-specific current magnitude is determined. Each change to a setting requires the patient to visit the physician, which naturally is time-consuming and burdensome.